ALUMINA. 



Colophonite {from the Greek kolophonia, a resin) is a 

 coarse granular variety, usually presenting iridescent hues 

 and a resinous luster. 



Aplome is a deep brown garnet, sometimes inclining to 

 orange. It presents the form in figure 4, and has a cleavage 

 parallel to the shorter diagonal of the faces. For this rea- 

 son it has been separated from the species garnet, and a cube 

 is considered its primary form. 



The different varieties fuse with more or less difficulty to 

 a dark vitreous globule. 



Dif. The vitreous luster of fractured garnet, without a 

 prismatic structure even in traces, and its usual dodecahedral 

 forms, are easy characters for distinguishing it.| Staurotide 

 differs in being infusible ; tourmaline has less specific grav- 

 ity ; idocrase fuses much more readily. 



Obs. Garnet occurs abundantly in mica slate, hornblende 

 slate, and gneiss, and somewhat less frequently in granite 

 and granular limestone ; sometimes in serpentine and lava. 

 *-*"The best precious garnets are from Ceylon and Greenland ; 

 cinnamon stone comes from Ceylon and Sweden ; grossularite 

 occurs in the Wilui river, Siberia, and at Tellemarken in Nor- 

 way ; green garnets are found at Swartzenberg, Saxony ; 

 melanite, in the Vesuvian lavas ; ouvarovite, at Bissersk in 

 Russia ; topazolite, at Mussa, Piedmont ; aplome, in Siberia, 

 on the Lena, and at Swartzenberg. 



In the United States, precious garnets, of small size, occur 

 at Hanover, N. H. ; and a clear and deep red variety, some- 

 times called pyrope, comes from Green's ^ creek, JDela ware 

 county, Perm. Dodecahedrons, of a dark red color, occur at 

 Haverhill, N. H. , some 1^ inches through ; also at New 

 Fane, Vt., still larger ; also Lyme, Conn. ; at Unity, Bruns- 

 wick, Streaked Mountain, and elsewhere, Maine ; at Monroe, 

 Conn. ; Bedford, Chesterfield, Barre, Brookfield, and Brim- 

 field, Mass. ; Dover, Dutchess county, Roger's? rock, Crown 

 Point, Essex county, Franklin, N. J. Cinnamon colored 

 crystals occur at Carlisle, Mass., transparent, and also at 

 Boxborough ; with idocrase at Parsonsfield, Phippsburg and 

 Rumford, Me. ; at Amherst, N. H. ; at Amity, N. Y., and 

 Franklin, N. J., ; at Dixon's quarry, seven miles from Wil- 

 mington, Del., in fine trapezohedral crystals. Melanite is 

 found at Franklin, N. J., and Germantown, Penn. Coloph- 



What is colophonite 1 What is aplome ? How is garnet distinguished 1 



